All lookups which include release-groups allow a type= argument to narrow down the release-groups.
All lookups which include releases also allow the type= argument, and a status= argument is allowed.

Note that the number of linked entities returned is always limited to 25,
if you need the remaining results, you will have to perform a browse request.

inc= arguments which affect subqueries

Some additional inc= parameters are supported to specify how much of the data about
the linked entities should be included:

- discids include discids for all media in the releases
- media include media for all releases, this includes the # of tracks on each medium.
- puids include puids for all recordings
- isrcs include isrcs for all recordings
- artist-credits include artists credits for all releases and recordings
- various-artists include only those releases where the artist appears on one of the tracks,
but not in the artist credit for the release itself (this is only valid on a
/ws/2/artist?inc=releases request).

Misc inc= arguments

- aliases include artist, label or work aliases
- tags, ratings include tags and/or ratings for the entity (not valid on releases)
- user-tags, user-ratings same as above, but only return the tags and/or ratings submitted by the specified user

Requests with user-tags or user-ratings require authentication. You can authenticate using HTTP Digest, use the same username and password used to access the main http://musicbrainz.org website.

Relationships

inc= arguments to include relationships work exactly like they do in /ws/1:

Non-MBID Lookups

Instead of MBIDs, you can also perform lookups using several other unique identifiers. However, because clashes sometimes occur, each of these lookups return a list of entities (there is no limit, all linked entities will be returned, paging is not supported).

discid

lookup: /discid/<discid>?inc=<INC>

A discid lookup returns a list of associated releases, the 'inc=' arguments supported are identical to a lookup request for a release.

A discid lookup can also return a list of CD stubs, if there are no matching releases in MusicBrainz. This is the default behaviour. If you do not want to see CD stubs, pass 'cdstubs=no.' CD stubs are contained within a <cdstub> element, and otherwise have the same form as a release. Note that CD stubs do not have artist credits, just artists.

puid, isrc

lookup: /puid/<puid>?inc=<INC>
lookup: /isrc/<isrc>?inc=<INC>

puid and isrc lookups return a list of recordings, the 'inc=' arguments supported are identical to a lookup request for a recording.

iswc

lookup: /iswc/<iswc>?inc=<INC>

An iswc lookup returns a list of works, the 'inc=' arguments supported are identical to a lookup request for a work.

Browse

Browse requests are a direct lookup of all the entities directly linked to another entity. (with directly linked I am referring to any relationship inherent in the database, so no ARs). For example, you may want to see all releases on netlabel ubiktune:

/ws/2/release?label=47e718e1-7ee4-460c-b1cc-1192a841c6e5

Note that browse requests are not searches, in order to browse all the releases on the ubiktune label you will need to know the MBID of ubiktune.

Linked entities

The following list shows which linked entities you can use in a browse request:

As a special case, release also allows track_artist, which is intended to allow you to browse various artist appearances for an artist. It will return any release where the artist appears in the artist_credit for a track, but NOT in the artist_credit for the entire release (as those would already have been returned in a request with artist=<MBID>).

〜 I think track_artist as described above is important, otherwise you will get client software requesting all recordings for an artist, followed by release requests for each of the recordings found earlier. --warp.

Release-groups can be filtered on type, and releases can be filtered on type and/or status. For example, if you want all the Live Bootleg releases by Metallica:

Note that filtering is mandatory, if you don't specify type or status the release and release-group resources will not return any results.

Paging

Browse requests are the only requests which support paging, any browse request supports an 'offset=' argument to get more results. Browse requests also support 'limit=', the default limit is 25, and you can increase that up to 100.

inc=

Just like with normal lookup requests, the server can be instructed to include more data about the entity using an 'inc=' argument. Supported values for inc= are:

In addition to the inc= values listed above, all entities (except release) support:

tags, ratings, user-tags, user-ratings

〜 we probably want to allow a few more inc= arguments here, though we can always add more later. --warp.

Release Type and Status

Any query which includes release-groups in the results can be filtered to only include release groups of a certain type. Any query which includes releases in the results can be filtered to only include releases of a certain type and/or status. Valid values are:

Submitting data

You can use the web service to submit certain kinds of data. Currently tags, ratings, PUIDs and ISRCs can be entered through the web service.

Authentication

All POST requests require authentication. You should authenticate using HTTP Digest, use the same username and password you use to access the main http://musicbrainz.org website. The realm is "webservice".

POST requests should always include a 'client' parameter in the URL (not the body). The value of 'client' should be the ID of the client software submitting data. This has to be the application's name and version number, not that of a client library (client libraries should use HTTP's User-Agent header). The recommended format is "application-version", where version does not contain a - character.

User Data

You can submit tags and ratings through the web service using POST requests. As described above, client software needs to identify itself using the 'client=' parameter. In the following examples I will use 'example.app-0.4.7' as the client identifier, this is obviously a fictitious client.

tags

To submit tags, perform a POST request to the /ws/2/tag url, like this:

Upon issuing this request MusicBrainz will create a single edit in the edit queue for applying these changes. These changes will not be automatically applied, though they will be applied if either no one votes against your changes, or your changes expire (this edit is applied on expiration).